This invention concerns a method for detecting the start of cascade locking in a four-wheel drive vehicle and the associated antilock brake control system (ABS).
In the conventional method of detecting the start of cascade locking, namely the tendency of all four wheels of a four-wheel drive vehicle to lock, a G-sensor detects vehicle deceleration. Corresponding signals are sent to an electric central processing unit (CPU), which computes vehicle speed from the deceleration figures. The vehicle speed so derived and the wheel speeds are compared so as to detect whether all four wheels are locked, and if so, an antilock operation is executed. This conventional method not only requires a G-sensor but also a complementary structure that includes a function to check for G-sensor malfunction.